Add support for backgrounding processes on the Mac

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index e31b91a053b1a476d75fb948dad0cb711fda65cc..819e8262a697e0c0f5b4f3e1d76a6bf6a1ed4b87 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -223,6 +223,9 @@ const char kDisableRemoteFonts[]            = "disable-remote-fonts";
 // Turns off the accessibility in the renderer.
 const char kDisableRendererAccessibility[]  = "disable-renderer-accessibility";
 
+// Prevent renderer process backgrounding when set.
+const char kDisableRendererBackgrounding[]  = "disable-renderer-backgrounding";
+
 // Disable the seccomp filter sandbox (seccomp-bpf) (Linux only).
 const char kDisableSeccompFilterSandbox[]   = "disable-seccomp-filter-sandbox";